 & Control & Treatment & Difference & All equal p-value \\ \hline 
  Site establishment year & 2008.24 & 2010.32 & 2.08 & 0.088 \\ 
 & (7.63) & (7.02) & (1.71) & \\ 
  Leakage & 79.11 & 77.11 & -2.00 & 0.116 \\ 
 & (211.28) & (284.55) & (35.10) & \\ 
  Venting & 156.21 & 225.64 & 69.42 & 0.554 \\ 
 & (297.78) & (498.34) & (57.26) & \\ 
  Gas production & 370.19 & 346.82 & -23.37 & 0.815 \\ 
 & (938.12) & (998.98) & (156.13) & \\ 
  Oil production & 212.92 & 112.47 & -100.45 & 0.343 \\ 
 & (1002.37) & (593.35) & (159.41) & \\ 
 \hline 
N: & 38 & 119 & & \\
